Field of the Invention
This invention relates to a flat panel display device used for note type personal computers, car navigation systems, portable television receiver sets and the like and, more particularly, to an improvement to a mechanical structure of a flat panel display device.
The structure of a conventional flat panel display device will be explained hereinafter with reference to FIG. 9. The flat panel display device 100 includes a passive display element, such as a liquid crystal display panel 105, and a back lighting system to illuminate the display panel 105.
The back lighting system is provided with a light guiding plate 107, and a lamp and its cover (not shown). The light guiding plate 107 is held in a resin frame 102. The display panel 105 is disposed on the light guiding plate 107 and the resin frame 102. The light guiding plate 107 conducts light beams from the lamp and irradiate them toward the panel 105. A driver circuit board 104 to generate driving signals for the display panel 105 is provided underneath the resin frame 102 and is connected to the panel 105 through a tape carrier package (TCP) 106. The TCP 106 comprises a flexible printed circuit film and a driver integrated circuit (IC) 161 mounted on the film. An upper surface peripheral and a surrounding edge wall of the flat panel display device 100 are covered with a metal bezel 108 assembled in a picture-frame form by L-shaped cross-section metal girders.
The light guiding plate 107, a receiving portion 121 of the resin frame 102 and the driver circuit board 104 are piled in thickness-direction structure in the conventional flat panel display device 100. A portable-type flat panel display device, however, is required to be smaller in size, thinner in thickness and lighter in weight than the conventional flat panel display device. In order to comply with those requirements, it is necessary to reduce the thickness of the receiving portion 121. Since an enclosing frame portion 122 of the resin frame 102 encloses the outer edge of the light guiding plate 107, it is also desirable that the width of the enclosing frame portion 122 (the distance between the outer edge surface of the light guiding plate 107 and that of the resin frame 102) is made as narrow as possible. Such structural changes may result in reduction of the mechanical strength of a flat panel display. Thus, it is difficult to secure sufficient reliability therefor against mechanical shocks or vibrations occurred in ordinary use or in use on a vehicle.
Further, the driver circuit board 104 is not prevented from electromagnetic interference with electronic components on the side of the display panel 100. Electromagnetic wave noises are not well suppressed in such a conventional flat panel display device. Particularly, electromagnetic wave noises increase as the mainstream of a flat panel display device is changed from the video graphic application (VGA; 480.times.640 pixels) to the super video graphic application (SVGA; 600.times.800 pixels). It is to be still changed from the excellent graphic application (XGA; 768.times.1024) to the super excellent graphic application (SXGA; 1024.times.1280). It is, therefore, indispensable to prevent the driver circuit board 104 from such electro-magnatic wave interference with other electronic components. Although the driver circuit board 104 may be contained in a metal case to avoid the interference, it does not always meet the requirements for flat panel display devices, such as small sizes and light weight.
An object of the present invention is to provide a flat panel display device with features of small size, thin thickness and light weight.
An object of the invention is to provide a flat panel display device with sufficient mechanical strength and high reliability. A frame of the flat panel display device is particularly strengthened to protect a display panel.
An object of the invention is to provide a flat panel display device which substantially prevents electromagnetic wave noises generated by a driver circuit board from interfering with other electronic components.
A first aspect of a flat panel display device in accordance with the present invention includes a substantially rectangle-shaped resin frame defined by four girders, a picture-frame like bezel, a display panel and a driver circuit board to drive the display panel. The front of the display panel is supported by the resin frame and the bezel while the driver circuit board is disposed under the back surface of the display panel. A metal sheet is provided between the driver circuit board and the display panel to shield electromagnetic wave noises generated from the driver circuit board. The metal sheet is engaged with or jointed to the resin frame to increase the strength of the resin frame as a reinforcement plate.
With the above-described structure, a portable-type flat panel display device is provided with features of a small size and lightweight and, at the same time, the metal sheet functions as a reinforcement plate so that the strength of the frame to protect the display panel can be increased and the reliability thereof can be also enhanced. Further, the metal sheet can effectively avoid leaking electromagnetic wave noises generated from the driver circuit board.
A second aspect of a flat panel display device in accordance with the invention is characterized in folded portions which is U-shaped in cross-section and is provided at the edges of the metal sheet to engage or joint the resin frame.
With this structure, even though the metal sheet is thin in thickness, a flat panel display device is provided with sufficient strength.
A third aspect of a flat panel display device in accordance with the invention is characterized in the metal sheet with a substantially right triangle shape, the slop of which is substantially consistent with a diagonal line of the display panel.
This particular structure materializes the flat panel display device with features of light weight and sufficient strength.
A fourth aspect of a flat panel display device in accordance with the invention is characterized in the metal sheet or a light guiding plate together therewith only disposed between the display panel and the driver circuit board.
This structure materializes the flat panel display device with a thin thickness.
A fifth aspect of a flat panel display device in accordance with this invention includes a resin frame defined by a substantial rectangle of four girders, a picture-frame like bezel and a display panel. The front of the display panel is supported by the resin frame and the bezel while the driver circuit board is disposed under the back surface of the display panel. A supporting member or a reinforcement plate made of a metal sheet is provided at a place corresponding to a diagonal line of the rectangle or at places corresponding to the corners thereof.
This structure materializes a flat panel display device with features of a small size and light weight. At the same time, the strength of the frame structure and the reliability thereof are maintained or increased to protect the display panel.
The above-stated and other objects and advantages of the invention will become apparent from the following description when taken with the accompanying drawings. It will be understood, however, that the drawings are for purposes of illustration and are not to be construed as defining the scope or limit of the invention, reference being had for the latter purpose to the claims appended hereto.